Advances for construction carrying amount.

No definition available.

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Namespace Prefix:	msex_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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- Definition

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

+ References

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- Definition

Face (par) amount of debt instrument at time of issuance.

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- Definition

The effective interest rate during the reporting period.

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- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

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- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

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- Definition

Amount, after deduction of unamortized premium (discount) and debt issuance cost, of long-term debt. Excludes lease obligation.

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- Definition

The number of shares issued or sold by the subsidiary or equity method investee per stock transaction.

+ References

No definition available.

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- Definition

Number of new stock issued during the period.

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- Definition

Equity impact of the value of new stock issued during the period. Includes shares issued in an initial public offering or a secondary public offering.

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Capitalization (Details) - USD ($) $ in Thousands	1 Months Ended			3 Months Ended
Capitalization (Details) - USD ($) $ in Thousands	Dec. 31, 2025	Sep. 30, 2024	May 31, 2024	Mar. 31, 2025	Mar. 31, 2024	Dec. 31, 2024
Capitalization [Line Items]
SRF loan amount				$ 140,000
Interest rate				5.43%	6.42%
Remaining availability of funds for borrowing				$ 106,000
Carrying amount of instruments				128,857		$ 129,602
Advances for construction carrying amount				22,700		22,600
New Jersey SRF Program [Member]
Capitalization [Line Items]
Borrowing amount				$ 300,000
Common Stock [Member]
Capitalization [Line Items]
Issuance of common stock (in Shares)				4,228	4,775
Issuance of common stock value				$ 200	$ 300
Common Stock [Member] \| Forecast [Member]
Capitalization [Line Items]
Issua and sale of shares (in Shares)	1,000,000
SRF Loan [Member]
Capitalization [Line Items]
SRF loan amount		$ 2,200	$ 5,600
Interest rate		0.00%	2.00%
Drawn amount				1,700
SRF Loan [Member] \| Tidewater [Member]
Capitalization [Line Items]
Drawn amount				100
Delaware SRF Loans [Member]
Capitalization [Line Items]
Drawn amount				4,900
Remaining availability of funds for borrowing				8,300
Long-Term Debt [Member]
Capitalization [Line Items]
Carrying amount of instruments				$ 229,000		$ 229,800